No-Frost Cooling Device

ABSTRACT

An evaporator unit for a no-frost cooling device which comprises an evaporator, a tubular heating device and a housing which surrounds the evaporator and the tubular heating device. Said tubular heating device comprises a plurality of parallel tubular sections which are connected together in such a manner that they form a single piece. Two parallel tubular sections which are directly adjacent to each other are located at the beginning and at the end of the tubular heating device.

The present invention relates to a no-frost cooling device. Such a subassembly conventionally comprises a carrier on which an evaporator and a heating device are accommodated. The subassembly is mounted in a cooling space of the cooling device close to the roof to delimit a chamber and communicates with the cooling space or cooling spaces through a forced ventilation system. The separation of the evaporator chamber from the cooling spaces allows the evaporator to warm up with the aid of the heating device when forced ventilation is switched off in order to defrost the ice which precipitates onto the evaporator during operation of the cooling device.

With a known subassembly of this type the heating device is embodied as a tubular heating device, i.e. in the form of a tube in which a poor electrical conductor is accommodated to which current can be applied to heat it up. With the known tubular heating device the tube is laid in a zigzag pattern on a heat-conducting sheet, i.e. it has a plurality of parallel sections, of which two adjacent sections are connected by a curved tube in each case. This means that the start and end of the tube are located on opposite sides of the heat-conducting sheet. In order to bring together the electrical leads connected to the two ends of the tube and take them out of the housing together, at least one of these supply leads must be laid over a distance approximately corresponding to the length of one edge of the heat transfer sheet into the housing and fixed, which makes an additional operation necessary after the tubular heating device has been installed in the housing.

The object of the present invention is to specify a no-frost cooling device with an evaporator subassembly for which this step can be omitted.

The fact that, in the invention, the start and end of the tubular heating device are located at two directly adjacent parallel tube sections enables electrical supply leads connected thereto to be brought out of the evaporator chamber on a short path which does not require the supply leads to be fixed separately to the support.

To lay the start and the end of the tubular heating device on parallel tube sections two parallel tube sections which are located on opposite sides of the tubular heating device are preferably to be directly connected by a tube bend.

With a first embodiment this tube bend runs in the same plane as the parallel tube sections. In this case the tube bends, exactly like the parallel tube sections, can be placed underneath the evaporator and can heat this from below.

According to a second embodiment the tube bend runs outside the plane of the parallel tube sections, preferably along a front face of the evaporator or across the evaporator.

To simply the installation of the tubular heating device it is preferably fixed at the height of the tube bends connecting the parallel tube sections to projections on the carrier. Such a fixing can especially make the conventional heat-conducting sheet superfluous as a carrier for the tubular heating device.

The projections preferably include at least a first projection which is in contact with the outer side on a center section of the bend, and a second projection which is in contact with the inner side at both ends of the bend, at the transition between the bend and the parallel tube sections connected to it. The second projection can also be divided up into two individual projections each in contact with one end of the bend.

To fix the tubular heating device to the carrier, the first projection preferably forms a hook surrounding the bend.

Further features and advantages of the invention emerge from the description of exemplary embodiments given below which refer to the enclosed figures. The figures show:

FIG. 1 a schematic section through the upper area of a no-frost cooling device in accordance with the present invention;

FIG. 2 a view of the tubular heating device as claimed in a first embodiment of the invention;

FIG. 3 a perspective view of the tubular heating device as claimed in a second embodiment;

FIG. 4 the tubular heating device from FIG. 2 mounted on a carrier;

FIG. 5 a detailed view illustrating the assembly of the tubular heating device as claimed in a modified embodiment; and

FIG. 6 a section of the detail from FIG. 5.

FIG. 1 shows a schematic section through the upper area of an inventive no-frost cooling device. The cooling device has a body 1 and a door 2, which are each implemented in a conventional manner as hollow bodies filled with a heat-insulating foam layer 3. The inside of the body 1 is divided by a likewise heat-insulating dividing wall 4 into an evaporator chamber 5 and a cooling compartment 6. The dividing wall 4 is formed by the floor of a carrier 7 for an evaporator subassembly, on which a laminar evaporator 8 known per se is mounted. The support 7 is mounted at a distance from the roof of the body 1 and, together with the side walls of the body 1, delimits the evaporator chamber 5. The carrier 7 also has an air inlet passage 9 on its side facing the door 2 and an air outlet passage 10 on its side 16 facing the rear wall of the body 1. In a rear area of the evaporator chamber 5, behind the air outlet passage 10 of the carrier 7, is accommodated a ventilator 11 with fan wheel 12 and motor 13, which extracts air from the evaporator chamber 5 and pushes it into an air duct 14.

In the cross section shown by way of an example in FIG. 1 the air duct 14 only extends through the dividing wall 4 and comes out in the cooling compartment 6 lying directly below it. The air duct 14 could alternatively also be routed within the rear wall of the body 1 and be provided with a plurality of passages through to the cooling compartment 6, via which the cold air flowing in the air duct is distributed evenly over the height of the cooling compartment 6. Furthermore a valve could be provided in the air duct 14 which directs the stream of cold air via different branches of the air duct, preferably to one of a number of compartments of the cooling device, for example the cooling compartment 6 and a freezer compartment not shown in the figure.

FIG. 2 shows a perspective view of a tubular heating device 20 accommodated on the carrier 7 below the evaporator 8. The tubular heating device 20 comprises a plurality of parallel linear tube sections 21 a, b, c, . . . , of which each one, with the exception of the rear left tube section 21 a, is connected by a tube bend 22 to an immediately adjacent section 21. Tube section 21 a is connected to the front right-hand linear section 21 r by an elongated tube bend 23 which extends over the entire width of the tubular heating device 20. Start and end of the tubular heating device 20 are located at adjacent parallel sections 21 a, b, so that supply leads 24 connected can be brought out on the shortest path from the evaporator chamber 5. A cube depicted by a dotted outline above the tubular heating device 20 symbolizes the evaporator 8.

The evaporator 8 can for example be a laminar evaporator known per se and not shown in detail here, which is arranged with laminations in parallel to the tube sections 21 or at right angles to them.

FIG. 3 shows a modified embodiment of the tubular heating device 20, in which the elongated tube bend 23 is routed out of the plane of the tube sections 21 and extends in front of the side of the evaporator 8 facing the air outlet opening 10.

FIG. 4 shows a perspective view of the tubular heating device 20 from FIG. 2 mounted on the carrier 7. The tube sections 21 lie on a base plate 25 of the carrier 7 which slopes slightly from a front wall 26 surrounding the air inlet opening 9 down to an edge 27. Behind the edge 27 is a more steeply sloping section 28 and a channel 29, in which—since it represents the lowest area of the base plate 25—evaporation water running off the evaporator 8 collects and flows out through an opening 30 in the floor of the channel to a vaporizer known per se and not described here. Each of the tube bends 22 facing towards the rear 16 of the carrier 7 is fixed to the base plate 25 by a group of three studs 31, of which one on the outside of the tube bend is in contact with the apex of the bend 22 and the other two are in contact with the inside of the bend in the transition area to the linear tube sections 21 in each case. The position of each tube bend 22 in the horizontal plane is exactly defined by the three studs.

Four forked support elements 32 projecting from the base plate 25 are provided to attach it to the evaporator 8, in that a coolant tube of the evaporator is inserted into the fork of the support element 32 and latches into a widened-out section of the fork.

FIG. 5 shows a detailed view of the floor of the carrier 7 in the region of the edge 27 in accordance with an embodiment, modified slightly from that shown in FIG. 4 with, in this embodiment, the two studs 31 in contact with the inner side of the tube bend 22 being replaced by a wide projection 33 tapering towards the top and the stud 31 in contact with the apex of the tube bend 22 having a recess 34, better able to be seen in the cross section depicted in FIG. 6, into which the tube bend 22 engages. The tubular heating device 20 is assembled by its tube bend 22 adjacent to the rear side first being positioned in a vertical orientation, as shown in FIGS. 5 and 6 respectively by dashed lines, on the section 28 of the base plate 25. In this case it is not important for the tube bend 22 to be placed exactly symmetrical in relation to the stud 31 and the projection 33; it is sufficient for the linear tube sections 21 connecting to the tube bend 22 just to be on different sides of the tip of the projection 33. If the tubular heating device 20 is pivoted against the base plate 25 into the position depicted by the solid line the tube bend centers itself on the projection 33 automatically, so that its apex comes to lie exactly in the recess 34 of the stud 31.

The recess 34 means that the stud 31 functions as a hook which prevents the tube bend 22 lifting away from the section 28. The wide projection 33 prevents the tube bend slipping to the left in FIG. 6, so that the tube bend cannot disengage from the recess 33 and the tubular heating device 20 is thus securely locked.

The front tube bends 22 facing towards the air inlet opening 9 can be locked by studs 31 and projections 33 similar to those shown in FIGS. 5 and 6 onto the base plate 25, but with these latter projections a recess into which the apex of the tube bend engages must be very flat to make it possible to press the tube bend 22′ between the studs and projections into a horizontal orientation.

As a result of the different inclines of the base plate 25 before and after the edge 27 the assembled tubular heating device 20 is subject to a bending stress which prevents a rattling of the tubular heating device as a result of the vibrations occurring during operation of the cooling device. 

1-8. (canceled)
 9. A no-frost cooling device having an evaporator, a tubular heating device and a housing for the evaporator and the tubular heating device, with the tubular heating device including a plurality of one piece contiguous substantially parallelly extending tube sections, the cooling device comprising at least two closely adjacent, parallely extending tube sections disposed at a first beginning portion and a second ending portion of the tubular heating device.
 10. The no-frost cooling device according to claim 8 wherein two parallel tube sections on opposite sides of the tubular heating device are directly connected by a tube bend.
 11. The no-frost cooling device according to claim 9 wherein the tube bend and the parallel tube sections are coplanar.
 12. The no-frost cooling device according to claim 9 wherein the tube bend extends outside the plane of the parallel tube sections.
 13. The no-frost cooling device according to claim 9 wherein the tubular heating device is fixed at the height of tube bends connecting the parallel tube sections to projections of the housing.
 14. The no-frost cooling device according to claim 12 wherein the projections include at least one first projection disposed in contact with an outer portion of a center section of the tube bend, and a second projection disposed in contact with an inner portion at both ends of the tube bend.
 15. The no-frost cooling device according to claim 13 wherein the first projection forms a hook surrounding the tube bend. 